If you're a lower level (Less than 20) player it's better to ask her to tag along. The path is linear and there are a couple of Draugrs on the way. The final level has a high level Draugr Death Overlord who uses Shouts.

If you're a high level (over 40) the Draugr Death Overlord will be replaced by a nameless Dragon Priest. He will be powerful, but he does not carry one of the collectable masks.

Speak with Eola after the Cave is cleared. She will task you with finding a feast to please Namira. She needs a priest and wants you to convince Brother Verulus (He can be found at the Halls of the Dead in Markarth) to join you to the Cave.

Once you bring him to the cave, Eola will hypnotize him and make him take a nap on the altar of Namira. She proceeds to request that you kill him and take the first bite.

Afterwards, Namira will speak to you (but only if you eat) and reward you with The Ring of Namira. The ring increases stamina by 50 and will give you increase in health and healthregeneration if you feed on a corpse (ring must be equipped to feed on a body, and a small menu will appear asking if you want to eat or search the body).

Warning* It is possible to kill Eola after you begin the quest and if you do so, the quest will automatically fail and you won't be able to repeat it afterwards.